1. Field of Endeavor
The present invention relates to a gas turbine system, in particular for a utility power plant.
2. Brief Description of the Related Art
Such a gas turbine system typically includes a combustion chamber, which, at least in an annular outlet region having a chamber inner wall and a chamber outer wall, radially delimits a combustion chamber gas path. Such a gas turbine system also typically includes a turbine, which, at least in a stationary annular inlet region having a turbine inner wall and a turbine outer wall, radially delimits a turbine gas path. To avoid excessive stress on components during transient operating states of the gas turbine system, the gas turbine system may also be provided with a radially inward and/or radially outward gap extending axially between the combustion chamber and the turbine, at which gap the inner and/or outer chamber wall and the inner and/or outer turbine wall end. To prevent entry of hot working gases into this gap, a cooling gas supply may also advantageously be provided, which via the gap introduces a cooling gas into the turbine gas path and/or into the combustion chamber gas path.
However, supplying cooling gas to the working gas of the gas turbine system directly reduces the power and efficiency thereof. It is therefore desirable to use as little cooling gas as possible.
Gas turbines are known from U.S. Pat. No. 6,283,713 B1 and GB 2,281,356 A, in which at least, for one row of guide vanes, the radially inwardly situated platforms of the individual guide vanes are contoured in such a way that an undulating surface profile results in the circumferential direction. In this manner the static pressure in the working gas may be influenced in such a way that, in the ideal case, in the circumferential direction an essentially constant static pressure results directly downstream from the row of guide vanes.
A gas turbine is known from U.S. Patent Application Pub. No. 2006/0034689 A1, in which a row of guide vanes has a plurality of airfoil members at its inlet side which protrude radially into the gas path. By use of these airfoil members, leakage flow which flows around the blade tips of upstream rotor blades may be reduced or deflected in the axial direction, thus increasing the efficiency of the gas turbine.